1. Field of the Invention
The present invention relates to a motor well adaptable for a CD-ROM driver, a DVD-ROM drive or others.
2. Related art
A brushless motor, disclosed in JP-A-8-331820, has been known for a motor used for the CD-ROM drive, for example. The brushless motor follows. A rotary shaft is supported with aid of a radial bearing as a sintered oil-impregnated bearing and a thrust plate within a cylindrical bearing housing. The radial bearing is located in the upper portion of the bearing housing. The inside diameter of the lower part of the bearing housing is larger than that of the upper part thereof. A dish-like thrust cap is mounted on the lower part of the bearing housing. A thrust plate is disposed between the lower end of the rotary shaft and the thrust cap.
The motor is capable of preventing bearing lubricating oil from flowing out of a thrust receiving portion since the dish-like thrust cap is mounted on the lower part of the bearing housing, and a thrust plate is disposed between the lower end of the rotary shaft and the thrust cap. In the radial bearing fixed to the bearing housing, the lubricating oil receives a pumping action with rotation of the shaft, and flows downwardly of the inner wall of the bearing housing. The oil thus flowing out reaches a portion where the thrust cap is attached to the bearing housing. Even if the thrust cap is attached in press fitting manner, a minute gap will possibly be formed between the cap and the housing since those members are separate members. If such a gap is present, oil will leak through the gap outside the thrust cap.
When a disc is attached to the disc hub integral with the rotary shaft, a force is applied to the fixing portion for the thrust cap and the bearing housing in a direction in which the thrust cap is pulled out. As a result, the oil is likely to flow outside from the fixing portion.